Refacto : Move genre and beat dropdown/select outside of sequencer component

[Babali42]

Issue :

The Sequencer component is no SRP (Single Responsibility Principle) at all.

To allow futur modification and features we must separate library managment (select beat or genre) from this component template and ts code.

Proposed Solution :

Move the select html control up and either use angular input or sequencerService dispatch to manage the state